1. Field of the Invention
The present invention relates to a resin casting or potting compound or adhesive for electrical and electronic components and modules, and in particular to a resin casting compound for thermally stressed electrical components.
2. Description of the Prior Art
Thermally stressed components are components that have high temperature peaks during operation. It is important for the useful life of such devices that as much heat as is possible be removed from the device by the resin casting or potting compound.
The cure hardening of epoxy resin compounds is an exothermic process, i.e. a chemical reaction that occurs while emitting heat. The temperature rise effected by the exothermy is correspondingly higher in relation to the poorer the heat dissipation properties of the cast specimen. The course of the cross-linking, which is normally very turbulent, is greatly moderated by the admixture of filling materials, thereby significantly reducing the exothermic temperature peak.
In the past, the thermal conductivity of the casting compound, for example an epoxy compound, has been enhanced by the addition of large quantities of aluminum oxide (Circuits Manufacturing, Feb. 1984, pages 89-96, particularly page 90). Given this larger addition of granular fillers, impact resistances that lie significantly below the values obtained by the unfilled resin system result. This reduction in the impact resistance of the resin compound results in a tendency to crack when it undergoes temperature shocks, thereby resulting in outages of cast components.